China patent application number 201220572475.4, filed by applicant, describes a fan including a housing, an air guiding device, an electric motor, and a fan blade, where the air guiding device, the electric motor, and the fan blade are arranged in the housing of the fan. The air guiding device includes a fixed ring, a fixed piece, and an air guiding sheet that is arranged between the fixed ring and the fixed piece. The electric motor is arranged in the fixed piece, the fan blade is arranged in the fixed ring, and the air guiding sheet is fit to the fan blade and is arranged on an upper part of the fan blade. An upper end of the housing is configured with an air-out channel, and the air-out channel is connected with an air flue in an air-out device. The air-out device has no fan blade, therefore, air generated by rotation of the fan blade is guided to the air-out channel by the air guiding sheet and is blown to the air flue of the air-out device. Thus, air is blown out from the air-out device. The fixed ring is fixed on the housing through a screw, where the screw may loosen because of shaking generated by the electric motor in a working state, which makes the fixed ring, not be firmly fixed and makes the fan run abnormally.